Just bought a very well taken care of 95 XJ 4x4 4.0L from a friend (non running with 125K on it} Got it running with a fuel pump. Have problem driving me crazy now though. Bought new tires which are balanced well. Drives very smooth and straight most of the time. However, as you drive, the vehicle will sometimes begin to bounce in the front end as if a tire was very much out of balance. Sometimes to the point that i feel like I should pull off the road. But then it will simply go away and begin driving smooth again. Alignment checked and is within spec. Drives straight as an arrow and smooth most of the time but usually begins pulling to the right at the same time the bouncing begins. I am not a mechanic but I am very comfortable and have a lot of experience working on vehicles, but just don't know what is causing this and don't want to just start changing everything up front hunting the problem. Please give me any ideas you may have. Also I have put new rotors and calipers up front and new brakes on the rear too. Did have this problem before brake replacement though. This problem seem to begin as you begin to come out of a right hand curve and begin to straighten the steering wheel. Thanks. tm147

 

Dealing with a similar issue myself right now. So far and I believe it's the only problem is my track bar ball socket is shot.

With the vehicle on it's own weight have someone rock the steering wheel back and forth. Doesn't take much. Watch for any play in the steering linkage,track bar,etc. I'll guess the ball joints,unit bearings,and maybe the control arm bushings are good considering the front end could be aligned.

Almost forgot. WELCOME to CF.

 

Shocks?

 

Thanks for the welcome EZEARL and the info. Your comment on alignment has made me rethink something. I did the alignment myself in my driveway with some quarter inch square stock clamped to my brake rotors and taking tow in/out measurements only. By doing this, the control arm bushings and track bar would not have even came into play in the alignment because I would have only been looking at position of front wheels, not the position of the entire front axle in relation to the rest of the vehicle. I will definately check the control arm bushings and the track bar ball and bushing. It really has to be the whole front axle moving a little bit. Great info. Thanks

 

The shocks are very old and I'm sure need to be replaced. Those are on the list to be done and new ones I'm sure would help with the bounce once it starts, but I'm thinking there is another culprit in there causing the bounce to start because of how smooth it drives when this problem is not going on. It truly feels almost like a new vehicle when things are working like they should. I may see if there is a deal somewhere on shocks and throw some on it. Thanks.

 

Try taking a measurement from the inner fender to a spot on the outside of the tire. Same places on both sides of course and see what you get.

Never checked but I believe the control arms keep the axle in position front to back. The track bar keeps it in the same position side to side. My control arms and bushings are good. My track bar ball stud has just enough play to cause a pretty good shimmy in certain circumstances.

 

You say bounce, as in up-down? Or side-side wobble? Up-down would most likely be a blown shock.

 

Just for giggles, try swapping the right front tire for the right rear and see if your bouncing changes. I've had a brand new tire be defective with a broken cord and they replaced it free of charge. I noticed it had more balancing weights on it than the other 3.

 

Kinda dealing with something similar with my 92. The shocks are original with 78000 miles on them, and are pretty well worn out.

Does it have the problem at low speed or higher speeds?

It could be a combination of track bar and shocks.

 

I think what Earl meant was that -assuming you had the alignment done by a shop - that the shop would have refused to do the alignment if any of the ball joints, control arms or hub bearings were out of spec. Considering that you did the alignment yourself, that assumption cannot be made. You need to check your ball joints, hub bearing and control arms as any one or a combination can contribute to what you're experiencing.

I'll agree with the others, consider the direction of the shimmying so you know where to focus and do the checking for play by turning the steering back and forth while watching.

 

"I think what Earl meant was that -assuming you had the alignment done by a shop - that the shop would have refused to do the alignment if any of the ball joints, control arms or hub bearings were out of spec. Considering that you did the alignment yourself, that assumption cannot be made."

Yep.

 

Thanks for all the replies and information. I'm going to check all the joints and bushings in the front end and also get new shocks. As I'm replacing all these parts, Ill try to drive it after each item is replaced so hopefully I can narrow down which item was the main problem. Maybe that will help someone else with the same problem. Ill post the results when I get all this replaced. This is an extra vehicle and its football season now, so it may be a little while.

 

Jack up the front and try jiggling the tires at 6 and 12. If it does wiggle, it's ball joints. If it wiggles at 9 and 3, it's your tie rods. I don't think it is your tie rods, but might as well check anyway

 

OK, I finally got me a bunch of parts to put on the XJ trying to fix the bounce. I put on new Gabriel shocks (rears are a pain in rear cause the factory bolts will break), Moog lower control arms, Moog track bar, and Moog sway bar polyurethane bushing kits. I still have Moog upper control arms and Moog ball joints to install but my bouncing problem has been fixed by what has been installed already.. All the Moog parts listed above were from Moog's Problem Solver line, not the economy line. Still got all those parts for right at $400. Came from Summit Racing.

 

I had a problem with a sudden vicious "Death Wobble" even after replacing everything I could think of up front, but my mechanic found it. The pitman arm was worn on the splines and would move back and forth! Not something that's normally a problem.